AERO6 calipers were designed for the specific purpose of providing big capacity braking with large diameter rotors for heavy weight and extreme duty vehicles. These kits are for thepopular 1963 thru 1987 Chevrolet & GM C10 / C15 Trucks with Wilwood's new 1 Piece Iron Drop Pro Spindles. AERO6 Big Brake Kits provide big stopping power for towing, off-road, and enhanced braking with wheel and tire upgrades. Kits are fully compatible with OE master cylinder output and ABS function. Directional staggered vane 14.00” rotors provide maximum cooling for sustained high heat durability. This kit contains hubs with 5 x 4.75” and 5 x 5.00” bolt circle.